Provided is a compound useful as an AMPK activator. The compound is a compound represented by the formula or a pharmaceutically acceptable salt thereof. In the formula, Y represents a substituted or unsubstituted alkyl group or the like； T represents -CR7= or -N=； U represents -CR8= or -N=； R2 represents a hydrogen atom or the like； R3 represents a halogen atom or the like； and R4, R7 and R8 independently represent a hydrogen atom or the like.
